1. Field of the Invention
This invention relates to a single wheel robot system and its control method. The robot is an intelligent self-control and thus self-balancing unicycle riding robot. The control method is the balance control method of the static imbalance unicycle robot.
2. Description of Related Art
Riding unicycle is complicated activity requiring a lot of advanced skill of balance. To obtain such capacity special study and training are needed. The study of autonomous robots which can imitate riding unicycle is the drive of such invention regarding self-control unicycle riding robots.
A single wheel robot is designed to imitate the activities of people riding a single wheel bicycle. The emergence of the bionic robot system is a result of rapid development and integration of artificial intelligence, intelligent control, machine design, robotics, and other related areas. A single wheel robot has obvious dynamic balance features different from a static balance robot. A single wheel robot has broad application prospects: With the complexity of its own unique balance of control problems, it can be used as a platform for unique features and tools in scientific research, display and entertainment; With its dynamic balance properties, it would be applied to complex terrain environment, for transport, rescue and detection; With its slim shape it would be used as monitoring robots, to realize the monitoring of narrow spaces; In the aerospace field, a special lunar vehicle can even be developed based on a single wheel robot.
Compared to the static balance robot (such as the four wheels mobile robot), a single wheel robot has the following salient features: 1) The robot's movement is based on the process of achieving a state of balance, that is, robots must be stabilized before they can carry out other movements. So this movement is a dynamic balancing process; the robot adjusts constantly in the vicinity of equilibrium point to maintain balance. While this increases the difficulty to control the robot, this enables the robot to complete many complex movement tasks of balance; 2) Since there is only one wheel, the hardware of a single wheel robot is simpler, lighter, the motion of the robot is also more flexible; 3) If robot arms, dexterous hands, a head, etc. are added to the robot body, the robot can be in a unique way to achieve the appropriate dynamic balance tasks, such as cycling in a very narrow path, riding off a very narrow beam, turning around in-situ, or even completing the difficult action of high-wire like a person.
The existing single wheel robots have mostly only driver and control layer on the robot's body as the basic functions, there is no sound macro-planning and visual functions, or the ability of transmitting information that needs to be processed to a host computer for processing. The robot does not have the ability to process such information either. For example, the robot “Murata Girl”, height 50 cm, weight 5 kg, speed of 5 cm/s, developed by Japan's Murata Manufacturing unicycle ride. For the control, the balance in left and right direction (roll) is kept through vertically rotating an inertia wheel of the robot body. For the front and rear direction (pitch), the motor of the body rotates the unicycle wheel through the chain of transmission to maintain balance. For the measurement, a tilt detecting gyro sensors is equipped in order to control the balance in two directions, respectively. In addition, it is equipped with ultrasonic sensors to detect obstacles, a blue tooth module to send and receive control instructions, a ceramic oscillator, the NTC Thermistor to test the temperature, etc. But “she” has no mechanical arms and dexterous hand to perform some tasks, and still has no ability of carrying out complex task such us visual mission. She transmits the information to the host computer for processing and lacks the flexibility to expand Debugging with castors components. Her wheel is the complicated chain drive mode. Her detection in only four single-axis gyro will produce the angle integral migration issue, and ultimately lead to system instability.